This invention relates to a film laminate structure for flexible containers. In particular, this invention relates to a multilayer laminate film structure for flexible containers capable of containing a liquid to be maintained and removed under sterile conditions.
Flexible containers are utilized in the medical industry for containing, inter alia, parenteral solutions, dialysis solutions, frozen drugs, nutrition products, respiratory therapy products, and plasma. Because these containers are utilized to contain fluids or solids that are introduced into a patient's body, it is necessary for the containers to be: essentially transparent; flexible; essentially free of extractables; and capable of maintaining the product contained therein under sterile conditions until the product is accessed or removed from the flexible container.
It is also important that the film used in constructing these containers is sufficiently strong so that containers constructed from the film have sufficient strength. Moreover, if the laminate film is to be constructed into a commercially viable flexible container, it is necessary that the flexible film can be run on some type of commercial production machine. One such machine is a form, fill and seal packaging machine. A form, fill and seal packaging machine seals the film to create a container having at least two sides. The side seals are typically effectuated by sealing the inside layer of the film to itself.
It may also be desirable to attach a fitment on the film structure to create a flexible container with a fitment. The fitment is typically heat sealed to the film. Accordingly, it may also be necessary that the film structure is heat sealable on its outside layer so that the fitment may be sealed thereto.
Because the film laminate is to be utilized for flexible containers that house a medical product that is to be introduced into a patient's body, it is necessary that the film structure does not contain chemicals that will be extracted by the medical product. This is an especially critical consideration when choosing an adhesive for bonding the laminate layers together. If a fitment is sealed to the outside wall of the container it is possible that there will be fluid communication between the product and the inner layers of the laminate. Thus, if the adhesive contains possible hazardous components that may be extractable, the film may not include a fitment sealed to the outside wall.
A further consideration in choosing the proper film for creating a flexible container is the product to be housed. In applications of the film as a frozen drug bag one must be concerned with the glass transition state of the film. Frozen drug bags are stored at approximately -25.degree. C. which falls below the glass transition state of certain film structures, e.g. polyvinyl chlorides. Accordingly, if these films are used for frozen drug bags they will be very brittle and may easily break.
Thus, there is a need for a film laminate structure for creating a sterile flexible container that overcomes the disadvantages of the prior art.